Transportation vehicle



I Nov. 9, Y1943. J. B. FELLABAUM 2,333,853

TRANSPORTATION VEHICLE Filed Aug'. 18, 1941 3 sheets-sheet 1 111,- N 1%@ T11@ m ---dmwnmi-----iil TRANSPORTATION vEHrcLE Fiied Aug. 18., 1941 s sneets-sneet www {WENT-0R Ma HIS HTTOF/YEY l Nav. 9, 1943.

J. a. FELLAeAuM TRANSPORTATION VEHICLE med Aug. 1e, 1941 J0 Wm:

mi: Ill-m -3 Sheets-Sheet 3 Patented Nov. 9, 1943V UNITED STATES y PATENT v OFFICE l v f TRANSPORTATION vEHIoLE John B. Fellavbauin,` Dayton, Ohio g Application-August `18, 1941, Serial No. 407,294

Y l 16 Claims. (Cl. 28o-,332)

This invention relates to laV transportation vehicle and more particularly to a vehicleprovided with caster-trucks.

In transporting freight-and other cargoes `over the highways Vor elsewhere, it is verydesirable toutilize equipment to the greatest advantage. Many of the freight haulers and trucking' companies use a tractorand a trailer`v` or a semitrailer ora. tandemtrailer and-various combinations thereof. Limitations are placedupon" the Figure 6 discloses anothermodication showing a side elevational view of a truck adaptedto be towed by a tongue, which truck is ,provided andapair of casterctrucks.. i i

Figure 7 is a top plan view vof the modification disclosed in Figure 6. g l

Figure 8 is an exploded lview'showing a stawith a pair of Wheels mountedon a xed axle tionary plate, a reciprocatory` and f oscillatory l size, the type and the maximum loads that may v be carried. For example, a limitation is placed upon the loadthat may be carried upon a single axle, which load isinfluenced bythe proximity of other axles. With this thought in"mind, `there has been a tendency to lengthen the loads by the use of trailers and semitrailersfconnectedin tandem. However, these have limitations caused by traffic hazards, resultingin traffic regulations. Furthermore, they have definite limitations' in that dimculty is experienced' in backing A"these various trailer arrangements;

An object of this invention is to provideamo? tor vehicle consisting of several units wherein the maximum load may be carried economically. l

Another object ofthis invention is to4 provide a composite-vehicle for'transportation` wherein the vehicle may be .easily Acontrolledin trailic.

Another object of this invention is to provide a supportvfor some of the unitsv of the compositeg vehicle, wherein these units are mounted forv Vapparent from the following description.v

1 spindle `placed at a considerable distance in front of the bearing line of the faces of the wheels, a construction which enables the wheels to swerve readily through 180 to either side of the line of draft. The bearing line,V as herev used, is ifa -line `on theV ground directly below and parallel to the axis ofthe wheels.

l The use-'of caster-trucks ,in -connection with trailers and trucks permits the equalization of the load on the several axles and'groups of Wheels l-to thereby vobtain the greatesteiiiciency in transportation, consistent with traffic regulations governing `the operation of trucks. Furthermore,

caster-trucks may be used in any arrangement In the drawings, Figure 1 is a side elevational 1 view of an articulated "motor tractor and truck-f trailer assembly.V

Figure 2 is a fragmentary top planfview taken substantially on the line 2--2 of Figure l.

Figure 3 is a transverse, cross sectional kview vmodification of a semi-trailerfattached to a tractor. Y l v `withapairof wheels mounted on a fixed axle,v lWhether the wheels be vmounted on the` tractor, ,on the trailer, on the trailer truck or any other unit associated with the transportation vehicle.V Such caster-trucksmay be mounted ahead of the 'fixed axle or to the rear or both, so Aas to be mounted under the load to support `part or all of whereinlauxiliary wheels arel provided to carry a small portion of the weight; but these auxiliary Wheels are definitely limited in their oscillatory movement, which may be satisfactory when these Ywheels are used on the tractor or the motor vejackkning` positions of the tractor with respectto thetruck and/or trailers. The present useof tractors permits the turning of the trucl:

or the trailer within its own space. The truck is controlled througha distance equal to a radius lextending from the wheels mounted on a fixed axle to the pivotal connection of the truck to the tractor. Such a prior art device is definitely limited in swinging movement to a degree substantiallr equal to the turning movement of the tractor provided with steering wheels; but cannot be used in turning atruck in a smaller space.

Such trucks having a limited-.swinging movement are not .practical for'use in trucks and trailers adapted to be towed by a tractor. k

Referring to the drawings, the tractor l-is used to supply power and support part of the weight of the load that may be hauled'in` a truck I2 partaking the nature of a trailer, having connected thereto a trailer I4. Either the truck I2 or the trailer I4 may be referred to 'as` aload the front end of the'slot 54.v

plate by suitable spring shackles. The springs support an axle 12, having mounted thereon a pair of wheels 14. Instead of a pair of wheels, there may be two wheels on each end, or there may be more, depending upon the load and the nature of the vehicle.

When the tractor exerts sof. as" to causethe king-.110112,52 'to beseated in By this arrangement, it can readily 'be seen that the axle I2 is located to the rear of the king bolt 52` measured in the direction of draft. Thus, the wheels 14, togetherv with the axle 12, the plate 56, the guides 58, etcetera, swerve sidewards whenever the direction of lmovement is changed, so as to cause l thewheelsiat allltimes to be substantially parallel carrying transportation unit drawn by a motorized,

tractor. The term truckf as used herein, designates a' load carrying: vehicle?` with allor part of th'e` power supplied' fro-mf. av separate powerunit. The tractorf! may Abe providedwith any suitable type of engineflocated under. the hood IS, such as a Diesel engine; gasoline enginefoil burning.l engineor anelectric?:fnotor.'

The wheels i8 are used in steeringthertractor and arecontrolledv by a steering wheel. actuated by a driverseate'diin thel cab 2B. Thewh'eels- 22 for-m `the 'drive wheels. Thes'era're. driven: from the motor throughy any suita'blefy transmission device. The' chassis 2'4- ofrfthe tractor supports. a fifth ywheel assembly including'.` one member. 26

mounted onrv the tractor and a. secondimember` 28 mounted on thechassis 3910i. the truck l2. Members 2'6 andi 28' areA pivotally attached. about a vertically disposed pivotforming a swivel, as is wellknownto those skilled'in the art.

The rear end` of the truck or trailer li2 has mounted thereon a pair of rigidbrackets 32? supporting av truck assembly including 'a pair of channel beamsor frame members 34, forming the chassis of a'sub-truck. The channel beams 341 are pivotally mounted at 35T about aZ horizontally? disposed pivot. This permits oscillatory movementy ofthe beams 34 with respect to'thefloadl, so as t0 take ca-reof unevennesslin the traveling surface,

" as'will appear more fully later;

vThe rear-ends of thev chann/el beams: 34' support a suitable leafspring 4U mounted. on a fixed` axle for'the wheels 42. A pair of wheels may be usedj'or fi'fi the load is too` heavy for -one pair,

- two or-three wheelsmay be usedon each end of theaxle, asl is well'v known to those skilled'inthe art. v

The front ends of the channel beams 34, as

viewed in Figure l, are mounted on a caster-truck assembly. Thi'scaster-truckassembly includes a vplate 5U fxedl'y attached-'to Vthercl'ianne'lsl 34 by rivets, spot'welding: or in any other suitablevmanner. In the centerof the' plate 50fis11ocated= an aperture receiving ark-ing bolt 521 The king' bolt extends througha s1'ot54ir`l aifloatingiplate 56. The lowerend of" the.' king bolt52 terminates in `a squarel orrectangular headlllf having faces. abutting` the under side'y of theplate 5.6A andv the edges guided byy a: pair of angle irons or guides 58, on'eon either' si'de of the slot 5'4. The angle v irons or guides. 58 extend. parallelxto the slot. and cooperate with the` edges of'A tllesdua-re` head 6U of. the king bolt to prevent rotation:thereof, unless the plate'561alsorotates, in which 'event the king bolt rotatesiwiththis plate.. 'Ihe plate 56: supports l beams v59.l having attachedy thereto springs v'i-. The ends-V offthe springs,l arel attached to thef f 'i2 and` the'partsycarriedthereby would readily` swerveif the wheels on'A onezsidewereto' hitlaJ to the line of draft as exerted upon the castertrucks by the king bolt. If it is found desirable to 'reverseffthee vehicle, thev -caster-truckqneed not 'i necessarily rotate throughslw-inthat thewheels 14, the axle '12, together with'the Flater-'56,v slide relative to the king bolt 52; so fas'ltoshift these parts'relative to the. king.l bolt -from'onejend of the` slot 54 to-theopposite endl Again, the axler and the wheels are located to the rearrof; the king bolt, measured in the direction of draft, which is reversed from the forward direction.I `In theabsenceof Aa restraining force, the. axl

r' is normalto the longitudinali axle' 1.2;;-so that whenv the wheels .14) are alignedz'with'the' wheels 42', the crank arm. 80 extendsin a direction par-` allel to thezlongitudinal.directioniof :the truck. 'I-hisf crank arm 80' carries la 'crank pin'= 88,` having mounted thereon a pair ofi pistonl rods'QU. supporting suitable pistons, not shown,ipositioned. ln

the dashtpots 92, pivotally mounted at941on suitable brackets 96C located in the channelsr34- v-'lihese.

dash pots are arranged to normally hold/the4 crank arm 8l) aligned with the longitudinaraxls of the truck. However, the dash potarrangement does not preclude' rotation' for swerving of the wheels aboutv the. king bolt 52. "As Aa matter of fact, the crank arm. 8U isy freezto'. swing through against the force exerted by. the dashpots if the manipulation of thetruck shouldrwarranvt sucharotation. 1^ In addition to thetruck I2;l'the.articulated transportation vehicler assemblyfshown in rFigure l 1 includes a trailer I4. The trailer'l4 is attached to the truck i2 by a horizontal pivot or hinge arrangementrincluding. thepivots II 00, one on either side of the trailer andthe truck. This arrangement causes the trailer I4 to be aligned with ,the

truck l2 at all times.` In orderv to supportthe weight of the trailer I4this trailer has been mounted upon a suitable block vIlllll supporting a l caster-truck. I l2 that isidenticalto thecasterl truckincluding the axle 12, the wheels=14 and. the parts associated therewith, as described in con,-

a forward draft on f the truck l2, the king bolt remains stationaryy in the plate 50; but the plate 56 slides rearwardly, Y

nection with the truck |2.- In4 the event vthe trailer I4 swerves to the right or the left in relsponse to a change of direction of the truck `I2 .towed by the tractor I0, the caster-truck I2 will swerve, sodas to permitthe trailer I i to swing to either side, `so that the body of the trailer I4 is always in .alignment withV the body of the truck |2.- The directionof .the movement of the truck I2 and the trailer I4 is governed by the relative `direction of :movement of the tractor I0 `with remounted upon a fixed axle relative to thertruck I2, excepting for the yielding of the springs 40.

If the tractor is caused to change its direction tothe left, the part of the assembly to the rear of thewheel 42 will swing to the right, that is,

`the trailer |4 swings uoutwardly in a direction opposite to the direction` of the swinging move- Amentrof-the truck, acute to the line of draft of the tractor. This articulated assembly is so convstructed and arranged that the tractor may fjack-knife with respect to the truck I2 and the trailer I4 about the pivot found in the fifth wheel, including members 26 and 28.r There is no .jack-l-lning effect laterally, as far as the relative positionofthe truck I2 with respect tothe trailer I4 is concerned. By the arrangement of the wheels shown, it is possible to arrange the distance between the axles so as to uniformly .divide the load and so as to have a uniform distance between the several axles.v By utilizing a caster-truck ortrucks, either infront or behind the fixed wheels 42, or both infront and behind, it is possible to maintain absolute vcontrol of the articulated transportation assembly in traic, in taking corners orcurves and in backing.

,The combination neednot necessarily consist of a tractor I0, a, truck I2 and a trailer I4. Re-

.ferring to the modification disclosed in Figure 5,

a tractor |20 is provided with a pairof upwardly directed brackets |22 hingedly supporting a trailer |24, identical in structure to the trailer fili,

excepting that in this modification the trailer |24 yhas the,;castertruck |26 located near the'rear ,end of the trailer |24. The trailer ,|24 is always f,

aligned with thetractor |20 so that when the tractor turns, the trailer |24 swingsj with it. The caster-truck |26 is identicalV to the caster-trucks vdescribed in connection with thepreferred eml bodiment. The Vcaster-truck being located near the rearcauses part of the load of the trailer to b e supported bythe rear end of the tractor VI 20, to thereby increase the traction of the drive wheels of the tractor.

Instead'of having a fixed axle under the truck I2, the truck I2 and the trailer i4 could be supported exclusively uponcaster-.trucka in which event the xed axle on the tractor, cooperating with the steering wheels, would govern the movement of the transportation unit. In that event, it would be necessary to utilize arhorizontalpivot arrangement or hinge arrangement Vfor interconnectingthe truck l2 and the tractor l0. The use of caster-trucks `is dependent upon the use lof one fixed axle, having wheelsmounted thereon 1 controlling the alignment of the chassis'mounted `on the caster-trucks,irrespective of where this xed axlemay be mounted, whether on the tractor, on the truck towed by the tractor, or on the trailer. i i i VIn the modiiication disclosed inFigures 6 and 7, 1

another type of truck assembly has Ibeen shown. In kthis truck assembly Ythe chassis |40 supports a .xed axle |42 near `one end thereof and a caster-truck assembly |44 `near the opposite end thereof, which .caster-truck assembly may be identical to the ones previously described. The rforward end of the chassis |40 has pivotally at-y tached theretoa Wishbone tongue I- pivotally mounted about the horizontal pivot |48 and terminating in a pivot |50 at the Aapex of the wish 1.1.0 spect to the direction` of the wheels 42 which are rthe arrangement of the caster-truck and the fixed axle' I 42 lcould -be reversed, that is, the fixed axle could be mounted at the front `and the caster-truck at the rear. Furthermore, the xed axle could be eliminated in its entirety, providing the pivotal connection between the truck |40 vandthe motivating vehicle-whether it be a tractor or some type of `a trailer unit connected to the tractorbe attached by the use of a horizontal hinge connection, so as to cause the body of `the truck I 40 and the motivating vehicle'to be aligned in a vertical plane. This hinge connection, of course, would require a double hinge connection, so as to take care of unevenness in the surface traversed.l d

In the preferred .embodiment and each of the "modifications, suitablebrakes may be provided for the wheels so as to apply the brakes to the caster-trucks, aswell as the other wheels. This may be accomplished by the use of' mechanical, electrical, hydraulic, vacuum or air brakes. The

.motivating force, irrespective of the nature of the brakes, may be supplied to the brakes on the individual wheels through the king bolt. The

Vbrake 4system has not been shown herein for the ,reason that this may form the subject matter of a separate application.v

`The above described preferred embodiment and several vmodifications have merely been shown for the purpose of illustration. Instead of utilizing a longitudinal slot that is straight, a curved or irregular shaped slot could be used. The slot wmay be dispensed with and the pivots supported upon suitable links or armsl having a fore and aft position, or the-frame of the caster-truck could be mounted for pivotal attachment intwo `positic'ans, one4 ,a fore position used in drivingr forward, and Vone an aft position used in reverse.

The same result may be obtained yby `providing `slidingsupports or .lost motion connection betweenvthe springs supporting, the axle and the vehicle. These are details any of which may be utilized to carry out the use ofl caster-truck that may rotate about a pivot offset with respect o to the axis joining the wheels.

Although the preferred modiicationof the device has been described, it will be understood that within the purview of this invention var- 'ious changes may be made in the form, details,

proportion and arrangement of parts, the combination" thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, jas disclosed and defined in the appended claims.

vHaving thus described my invention, I claim: `1. Atransportation assembly including a tractor having a pair of steering wheels and a pair vof driving wheels, a semitruck, means; for interconnecting the'front end of they truck tothe tractor, said means forming a Vswivel connection between the tractor andthe truck allowing the truck to oscillate about a vertically disposed pivot, said truck including a sub-truck pivotally attached to the aforementioned truck so as to support part of the load, said sub-truck including a frame, a pair of supporting wheels and an-axle therefor, said axle being non-rotatably attached to one end of said frame, and a caster-truck, means for interconnecting the caster-truck to the other end of the frame, said last'mentioned means including a vertically disposed pivot, said caster-truck including wheels which turn about an axle held in a frame which itself turns on said Vertical pivot placed a considerable distance in front of the bearing line of the faces of the wheels, which frame permits the wheels to swerve readily through 180 to either side of the line of draft, said interconnecting means permitting a longitudinal movement between the frame of the caster-truck and the pivot so as to permit the axis ,ofthe wheels ofthe caster-truck to shift from one side of the pivot to the opposite side of the pivot without rotating the frame through 180. e k,

2,. A transportation assembly including a tractor having a pair of steering wheels and a pair of driving wheels, a trailer assembly, and means for interconnecting the iront end of the trailer assembly to the tractor, said means forming a flexible coupling between the tractor and the `trailer' assembly. said trailerl assembly including a caster-truck for supporting at leasta part of the load, said caster-truck includingA wheels which turn about an axle held in a frame which itself turns on a vertical pivot placed a considerable distance in front of the bearing line of the faces of the Wheels, which frame permits the Wheels to swerve readily through ,18.0"l to either side of the line ofdraft, the frame of the Ycaster-,truck having a longitudinal sliding movement with respect to the pivot so as' to shift the relative position of thel axle, of the castertruck from one side of the pivot tothe opposite side of the pivot without rotating the frame through 180.

3. A transportation assembly including a tractor, a fifth wheel member mounted on the tractOl, a load carrying transportation unit including a second fifth Wheel member cooperating with kthe first fifth Wheel member to form a pivotal interconnection for swinging movement .about a Vertical 'pivot disposed intermediate the tractor and the load carrying transportation unit, said load carrying transportation unit including a caster-truck for supporting part of the load of the load carrying transportation unit, said caster-truck including wheels which turn about an axle held in a frame which itself turns on a vertical pivot placed a considerable distance in front of the bearing line of the faces of the wheels, which frame permits the wheels to swerve readily through 180 to either side of the line of draft, the frame of the caster-truck having a longitudinal sliding movement with respect to thepivot .so as to shift the relative position of Athe axle oi the caster-truck from one side of the pivot to the Opposite side of the pivot without rotating the frame through 180. v

4. A transportation assembly including a mo- `torized tractor,` a load carrying transportation unit, `means for pivotally interconnecting the tractor to the load carrying transportation unit, said load carrying transportation unit including a caster-truck for supporting part of the load in front of the bearing vline of the faces of the Wheels, which frame permits the wheels to swerve readily through to either side of the line of draft, the frame of theY caster-truck having a longitudinal sliding movement with respect to the pivot so as to shift the relative position of the axle of the caster-truck from one side of the pivot to the opposite side of the pivot with out rotating the frame through 180. V 5. A transportation assembly including a inotorized tractor and a load carrying transportation unit, flexible means for interconnecting the transportation unit to the tractor, said transportation unit including a load carrying axle, Wheels for supporting said axle, and acastertruck mounted intermediate the load carrying axle and the tractor, said caster-truck supporting a part of the load of the transportationunit,

said caster-truck including wheels which turn y about an axle held in a frame whichv itself turns on a vertical pivot placed a considerable clistance in front of the bearing `line of the faces y of the wheels, which frame permits the Wheels to swerve readily through l180 to either side of the line of draft, the frame of the caster-truck tru'ck including wheels which turnv about an axle held in a frame," means for interconnecting the frame and the chassis Aincluding a Vertical pivot slidingly engaging the frame so that the pivot'ls placed a considerable distance in frontjof the bearing line of the faces of the Wheels', which frame permitsl the Wheels `to swerve'readily through 180 to either side 0f the line'of draft,v

an axle mounted intermediate the caster-truck and the tractor, means Afor interconnecting the axle to the chassis of the transportation unit, and

wheels rotatably mounted on the'axle for sup'- porting a part of the load'of the transportationr unit. 7. A transportation assembly including a motorized tractor and a load Acarrying transportation unit adapted to be drawn by the motorized tractoryflexible means for interconnecting* the transportation unit to the tractor, said. transportation unit including ay load carrying; axle,

wheels for supporting said axle, and a castertruck mounted intermediate the load carrying axle and the tractor, said caster-truck supporting a part of the load of the transportation unit, and a second caster-truck mounted to the rear of the load carrying axle for supporting a part of the load of the transportation unit, each of said caster-trucks including wheels which turn' about an axle held in a frame which itself turns on a vertical pivot placed a considerable distance in front of the bearing line' of the faces of the wheels, which frame permits the wheels' to swerve readily through 180 to either side of the line of draft, and means for reversing ythe relative position of the pivot with respect tothe frame, "soas to shift thepi'v'ct from a position inv--frontiofthe axle to a like positionV to the rear "ofl the axle when reversing the direction of move- -ment of the transportation; unitto thereby elim- '.'inate the swerving oi` -'th`eaxlethroughvloi.

:8. A transportationfassemblyv including'a motorized tractoig-a load' carrying transportation iunit'adaptedftolbe drawn' by the motorized' trac j'jou'rnalledv onthe axle, said load carrying wheels together with the axle and the second plate caus- @ingl the 4second plate 'to slide rearwardly with respect to the direction offdraft toi seat` thelking bolt in engagement with the forward end of the slot forming a pivot about which the second plate, the axle and the wheels may'swerve to either side in response to changes in the direction of draft.

9. A transportation assembly including a motorized tractor, a load carrying transportation unit and flexible means for interconnecting the load carrying transportation unit to the tractor, said load lcarrying transportation unit including a chassis, a caster-truck assembly mounted un-` derneath the chassis, said caster-truck assembly including a fixed load carrying plate havingan aperture in the center thereof, a king bolt extending through said aperture, a second plate underlying the first-mentioned plate, said second plate being provided with a longitudinal' slot receiving the king bolt, means for mounting load carrying `Wheels underneath said second plate,

the longitudinal axis of the axle means about which said wheels rotate being aligned with and underlying the center of said slot, said load carrying wheels together with said second plate causing the second plate to slide rearwardly with respect to the direction of draft to seat the king bolt in engagement with the forward end of the slo-t forming a pivot about which said second plate and the wheels may swerve to either side in response to changes in the direction of draft, and means for resisting swerving movement of said second plate with respect to the first plate.

10. A transportation assembly including a motorized tractor, a load carrying transportation unit andflexible means for nterconnectingthe load carrying transportation unit to` the tractor, said load carrying transportation unit including a chassis, a caster-truck assemblymounted underneath the chassis, said caster-truck assembly including a xed load carrying plate having an aperture in the center thereof, a king bolt extending through said aperture, a second plate underlying the first-mentioned plate, said second plate being provided with a longitudinal slot receiving the king bolt, means for mounting load carrying Wheels underneath said second plate,

I the longitudinal axis ofthe axle means about which said wheels rotate being aligned with and underlying the center of said slot, said load carrying wheels together with said second plate causing the second plate to slide rearwardly with respect to the direction ,of draft to seat the king causing the king bolt to rotate with the second plate, acrank arm fjlxedly attached to the king bolt,"and a dash pot assembly interconnected to the crank arm, said dash pot assembly tending to align the slot with respect to the longitudinal axis of the load carrying transportationv unit.

ll. A transportation assembly including a motorized tractor, a load carrying transportation unit and flexible means for interconnecting the load carrying transportation unit tothe tractor, said load carrying transportation unit including avchassis, a caster-truck assembly mounted underneath the chassis, said caster-truck assembly including a frame,` an axlecarried by the frame, load carrying wheels rotatably mounted on the axle, and pivotal means for interconnecting said frame to the chassis or the iced carrying transportation unit, said pivot beinglocatedahead of the axle in the-direction of draft, said pivot permitting the frame and the wheels carried thereby to swerve through about said pivot, said pivotal means cooperating with the castertruck frame to permit an axial movement `of he frame with respect to the pivot so as to shift the pivot with respect to said axle so as to adjust the pivot from one side of the axle to the opposite side ofthe axle in response to a reversal of the direction of movement.

12. Atransportation assembly including a motorized tracto-r, a load carrying transportation unit and flexible means for interconnecting the load carrying transportation unit to the tractor, said load carrying transportation unit including a chassis, a caster-truck assembly mounted underneath the chassis, said caster-truck assembly including a frame, an axle carried by the frame, load carrying wheels rotatably mounted on the axle,y and pivo-tal means for interconnecting said frame to the chassis of the load carrying transportation unit, said pivot being located ahead of the axle in the direction of draft, said pivot permitting the frame and the wheels carried thereby to swerve through 180 vabout said pivot, and means for restricting the free swerving movement of said frameand the wheels carried thereby, said means tending to align the axle normal to the longitudinal axis of the load carrying transportation unit. l

13. A transportation assembly including a motorized tractor, a load carrying transportation unit and 'flexible means for interconnecting the load carrying transportation unit t0 the tractor, said load carrying transportation unit including a chassis, a caster-truck assembly mounted underneath the chassis, said caster-truck assembly including a pivotally mounted frame, a pivot attached to said chassis, adjustable means for interconnecting the pivot to the frame, said adtion offset tov the rear in the direction of the` line of draft when the pivot is in one position so as tor permit the wheels to swerve in response to changes in the direction of the line of draft,

'said frame and the load carrying wheels being free to swerve through 180 said frame shifting g with respect to the pivot to the opposite extreme position in response to a reversal in the direction of the line of draft so as to shift the pivotal connection from one side of the axis of rotation to the opposite side thereof.

14. `A transportation assembly including a motorized tractor, a loadA carrying transportation unit and flexible means for interconnecting the load carrying transportation unit to the tractor, 'said load carrying transportation unit includin-g a chassis, a caster-truck assembly mounted underneath the chassis, said caster-truck assembly axis in response to a reversal in the direction of the line of draft, and dash pot means restricting the free swerving movement of the frame and the load carrying Wheels.

15. A load carrying caster-truck assembly, said caster-truck assembly including a king bolt, means in which saidwkingbolt is` .'lou'rna.Mini,AA a fraude,- an` axle,i means. fox: attaching the fname to theaxle, said frameincluding a slot t'lnfotlshv which; the: king bolt projects,y the axlel extending normal tof the longitudinal axisgof the. slot, yllld load. carrying. wheelsjourxialledsonsaid axlo, ,sa1d l framemoving relativetotliefkingfbo'ltin to movement of the king, bolt so as trcguse lthe king bolt to be seated-in ther forward: ad ot the Vslot measured inthe'direction of. draft..

normal to the longitudinal axis of the/51011 lo carrying Wheels journallecl4 on-- said axleQsgid .frame moving relative tothe king bolt in response to movement of the king bolt so as-v to causev the king bolt to be seated inthe: forward end ot they slot measured` in the direction of draf@ and means restraining .thefree pivotal movement of the frame, Esaid means stabilizing the lframe and thepartscarried thereby.- Y

-. JOHN nFEuABAUM v 

